Method of making zinc oxid.



L'. S. HUGHES.

METHOD OF MAKING ZINC OXID- APPLICATION FILED NOV.13, 190s. nmmwnn 110mm, 1908. 920,337.

Patented May 4, 1909.

WITNESSES 4; ATTORNEY.

Forum-ED STATES PATENT OFFICE.

LOUIS S. HUGHES, OF 'JOPLIN, MISSOURI, ASSIGNOR To PIOHER LEAD COMPANY, OF JOPLIN,

MISSOURI, A GORPORATIONOF MISSOURI.

METHOD OF MAKING ZINC OXID.

Specification of Letters Patent. Application fllcdNov'ember 13, 1906, Serial No. 343,284. Renewed November 27, 1908.

Patented May 4, 1909.

Serial No. 464,785.

To alt whom it may concern:

Be it known that I, LOUIS S. HUerIEs, a citizen of the United States of America, residing in Joplin, in the county of Jasper and State of Missouri, have invented a certain new and useful Improvement in Methods of Making Zinc Oxid, of which the following is a. true and exact description, reference belng had to the accompanying drawings, which form a part thereof.

My inventiomrelates to the manufacture of zinc oxid from zinc carbonate having special reference of c'ourseto the native carbonate ores. v

The object of my inventionis to provide for a rapid, efficient, and economical manufacture of zinc oxid from such ores my improved method, broadly speaking, consisting in finely dividing the carbonate, maintainin the furnace at an internal temperature suf-' ficient to decompose the carbonate with a production of zinc oxid ZnO and carbonic acid G0,. I then inject the finely divided carbonate into the heat zone of the furnace in a fine state of separation, as by means of a feed jet of air or vapor, a rapid decomposition of the ore taking place and zinc oxid in an exceedingly fine state of division passing out of the furnace with the gases is then separated by screening, the separation of the heavy impurities being effected by subsidence either in the furnace or in the fines in-- tervening between thefurnace and the screen system, and for the best results my process should be practiced in a vertical furnace, the air or vapor jet being directed upward from the bottom of the furnace and provision made for the extraction of heavy impurities from the bottom of the furnace.

It is an important feature of my invention that the furnace should be maintained attemperatures-not abovc1300 F. for the reason that the body of the zinc oxid is impaired by temperatures materially in excess of that amount'and for the further reasons that a greater furnace heat develops a greater brilliance of color in any iron oxid which may remain in admixture with the zinc oxid and the further, reason that cadmium which is very frequently found in zinc ores is not burned to an oxid at this temperature while at higher temperatures it is oxidized and forms a discolormg agent. I

My process is most advantageously carried into effect in furnaces of the character described in my copending applications, one filed March 20, 1906 Serial Number 306,954 and the other filed October 22, 1906, Serial l\ umber 339,894, and I have illustrated such a furnacein the drawings forming part of, this specification and in whicha Figure 1 is a side elevation of a furnace with connected fines and screen system, the

furnace being partly shown in vertical secton, and Flg. 2 IS a cross-section on the llne A indicates the cylindrical walls of the furnace formed of thin unlined sheet metal and provided with a hopper shaped bottom A of the same material having one or more openings indicated at A for the admission of air and the outlet of unburned particles which settle in the furnace; A indicating the normally closed opening by which access is had to the interior of the furnace.

D is an air jet pipe directed axially upward from the bottom ofthe furnaceand supplied by an air pipe B.

C is a flue leading from the top of the furnace provided with settling chambers C C and connecting, as shown, to a draft fan D, with the flues C C the latter flue having hoppers C-*, C, opening into its bottom for the reception of the zinc oxid and connect-- iug at'top with screen bags indicated at E, E, through whlch the furnace gases escape.

F indicates a gas pipe supplying an an- "nular gas ring F'- having pro ecting from it a series of burner nozzles F F these burner nozzles projecting 'into the burner tubes G, G, which extend through the walls of the furnace and beyond the same, the inner ends of the burner tubes having overhangs, as indicated at G.

G is a hopper in which the finely divided ore is placed and which communicates with the interior of the furnace through a chute H having a trough like end H which projects to or nearly tothe center of the furnace so as to deliver the ore directlyinto the upwardly movingair jet from the et pipe.

I is a gate for regulating the feed and J a rapping or vibrating device acting on the hopper and chute so as to keep the metal of which they are made in vibration and insure a constant and even feed of ore.

In operation the furnace is heated by the admission of the mixed gas and an enterlng through the burner tubes G and forming a rounded and jacketed, especially in the lower part of the furnace, by air indicated at L, this air entering through the opening A. The finely divided .zinc carbonate is placed in the hopper H and fed through the chute H and trough H to the center of the air jet issuing from the pipe B by which it is projected into the heat zone of the furnace in a fine state of separation as well as division.

' tling chamber C" and finally being separated from each other in the screen system E, the

' oxid collecting in the hoppers C Having now described my invention what I claim as new and desire to secure by Letters Patent is l. The method of manufacturing zinc OXld from ZlIlC carbonate which conslsts 1n finely dividing the carbonate, maintaininga furnace at an internal temperature suflicient to decompose the carbonate by an internal gas flame, injecting the finely divided carbonate into the-heated portions of the furnace to decompose it, separating the zinc oxid and furnace gases from impurities by subsidence and separating the zinc oxi-d from the gases by screening.

2. The method of manufacturing .zinc

I oXid from zinc carbonate which consists in finely dividing the carbonate, maintaining a furnace at an internalfitemperature sufiicient to decompose the carbonate by an internal gas flame, injecting the finely divided 'carbonate into theheated portion of the'furnace by a jet of air or vapor directed upward from the bottom of the furnace to decompose it, and separating the zinc oxid and furnace gases from the gases by screening.

The method of manufacturing zinc oxid from zinc carbonate which consists in finely dividing the carbonate, maintaining a furnace at an internal temperature sufficient to decompose the carbonate by an internal gas flame, cooling the furnace to maintain its temperature below that'at which the .zinc oxid is impaired by heat and heat products, injecting the finely divided carbonate into the heated portion of the furnace to decompose it, separating the zinc oxid and furnace gases from impurities by subsidence and separating the zinc 02nd from the gases by screening. 7

LOUIS S. HUGHES. Witnesses BELLE" SPARKS, JERE. CHARLOW. I 

